Retarded-release valve.



J. S. GUSTER.

RETARDED RELEASE VALVE.

APPLICATION FILED FEB. I 1905.

1,003,990, Patented Sept. 26,1911.

cnLulABlA PLANoflRAPIl 50-. WASHINGTON. l1. c4

.UNITED STA OFFICE.

JOHN S. CUSTER, F PITTSBURG, PENNSYLVANIA, ASSIGNOR TO THE WESTINGHOUSE AIR BRAKE COMPANY, OF PITTSBURG, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

RETARDED-RELEASE VALVE.

To all whom it may concern:

citizen of the United States, residing in Pittsburg, county of Allegheny, and State of Pennsylvania, have invented a certain new and useful Improvement in Retarded- Release Valves, of which improvement the following is a specification.

This invention relates to automatic fluid pressure brakes, and has for its object to provide an improved valve device for controlling the exhaust from the triple valve, and operating at the time of releasing the brakes to hold the exhaust outlet from the triple valve closed or restricted for a limited period of time on the forward cars, thereby retarding the release upon the front end and securing a substantially simultaneous release of the brakes throughout the entire length of the train.

With the present standard automatic air brake apparatus, as is well known, the release movement of the triple valve is produced by an increase in train pipe pressure which accumulates rapidly at the head end of the train pipe, but requires some little time to travel to and actuate the triple valves at the rear end, especially on long trains, the result of this being that when a release is made before coming to a full stop, the head brakes are often released considerably in advance of the rear brakes thereby permitting a surging ahead of the forward end of the train, while the brakes on the rear cars are still applied, which action is productive of violent shocks and strains and often causes a break-in-two of the train.

It has heretofore been proposed to provide a valve device operated by the increase in train pipe pressure in releasing brakes for restricting the exhaust port of the triple valves on the forward cars of the train, the valve device being subject to the opposing pressures of the train pipe on one side which carries the valve to its retarded release position, and to the auxiliary reservoir pressure upon the opposite side, a yielding resistance spring being employed upon the auxiliary reservoir side to return the valve to fully open the exhaust port when the opposing fluid pressures are substantially equalized.

According to my improvement, I provide means operated by the triple valve for vary ing the pressure upon one side of the re- Specification of Letters Patent.

Application filed February 1, 1905.

Patented Sept. 26, 1911.

Serial No. 243,641.

tarded release valve device, whereby the same occupies its closed or restricted posltlon for retarding the release at the time the triple valve is moved to release position, after which the pressure equalizes upon the release valve device in a longer or shorter period according to the position of the device in the train from front toward the rear end, and the spring then returns said valve to its normal full release position.

In the accompanying drawing, Figure 1 shows in section a triple valve device and a retarded release valve device embodying my improwments, the section of the triple valve being taken on the line w-a: of Fig. 3, with the valve in normal full release position; Fig. 2 a similar sectional view, taken on the line w- '1 --m of Fig. 3, with the valve in position for service application of the brakes; Fig. 3 a plan of the slide valve seat of the triple valve; and Fig. 4 a face view of the main slide valve.

As shown in the drawing, the triple valve device comprises the usual casing having the piston chamber 2 connected to the train pipe 1, and valvechamber 3 adapted to communicate at 6 with the auxiliary reservoir, and containing piston 4, stem 5, main slide valve 7, and graduating slide valve 8. The main slide valve is provided with the usual service port 12 and exhaust cavity 27 for connecting the brake cylinder passage 9 and port 10 with exhaust port 11 of the valve seat in release position, all of which may be of the ordinary well known standard construction.

According to the preferred form of my improvement, I provide a retarded release valve device 15 comprising a casing containing a movable abutment or piston and a valve 21, the chamber 19 on one side of said piston being connected by pipe 16 with the train pipe 1, and the opposite side of the piston communicating through pipe 17 with an additional port 13 in the slide valve seat of the triple valve. The slide valve 7 also has a cavity 28 for connecting the port 13 with an additional exhaust port 141 in service position. A. pipe 18 connects the triple valve exhaust port 11. with port 23 of the retarded release valve and the slide valve 21 has a cavity 26 for opening the triple valve exhaust to the atmosphere through port 22 in the normal position of the valve, the spring 25 operating to hold the piston and valve in this normal fullrelease position.

when the pressures are equalized upon opposite sides of the piston 20. When the sys tem is fully charged with fluid under pressure, and the parts are in full release position, as indicated in Fig. 1, the port 13 is open, so that communication is established between the auxiliary reservoir and the release valve chamber, the piston 20 then being balanced by the opposing pressures of the auxiliary reservoir and the train pipe and held by spring 25 in its full release position.

Vhen the train pipe pressure is reduced for applying the brakes, and the triple valve slide valve moves out to service application position in the usual manner, the cavity '28 connects ports 13 and 14, as indicated in Fig. 2, thereby releasing the air from one side of the piston 20 to the atmosphere, whereupon the train pipe pressure upon the opposite side immediately moves the piston and valve to its inner retarded release position, in which the triple valve exhaust is closed or restricted and the spring 25 compressed, as indicated in Fig. 2. IV hen the brake valve is turned to full release position a large volume of air from the main reservoir flows into the train pipe, increasing the pressure therein very rapidly at the head end and causing the forward triple valves to move promptly to release position. This movement opens the port 13 for supplying air from the auxiliary reservoir to the release valve piston, but as the train pipe pressure upon the opposite side of said piston in creases more rapidly at the head end of the train than does the auxiliary reservoir pressure, it is evident that the valve 21 will remain in its retarded release position with the triple valve exhaust closed or restricted until the train pipe and auxiliary reservoir pressures substantially equalize, then the spring 25 operates to return the retarded release valve and open the brake cylinder exhaust. As the wave of increased train pipe pressure flows toward the rear of the train it is retarded by frictional resistance along the pipe until at the end of long trains the rate of increase is greatly diminished and quite a period of time is required to effect the release movement of the rear triple valves. During this interval the brake cylinder exhaust upon the forward cars is held closed by the retarded release valve under the more rapid rise in train pipe pressure. At the rear of the train the rate of increase is so slow that the pressures upon the opposite sides of the release valve piston substantially equalize immediately after the triple valve moves to release position, consequently the exhaust port will then be immediately opened by the action of the spring 25, while at intermediate positions in the train the interval during which the exhaust port is held closed will vary in proportion to the rate of increase or head of train pipe pressure corresponding to the relative distance from the front to the rear of the train, whereby a substantially simultaneous release of all the brakes will be secured.

By means of venting the chamber on one side of the release valve piston at the time of applying the brakes, or before the triple valve is moved to release position, the release valve is positively held in its retarded position, so that it is not necessary to depend upon the excess in train pipe pressure at the time of releasing, for moving the release valve device to its retarded position, and this is an important feature, as it makes the device more sensitive and renders the same effective for a much greater distance from the head toward the rear of long trains.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent is 1. In a fluid pressure brake, the combination with a triple valve having an exhaust port, of a movable abutment subject to train pipe pressure and valve for controlling said exhaust port, and means operated by the triple valve for varying the pressure upon one side of said abutment.

2. In a fluid pressure brake, the combination with a triple valve having an exhaust port, of a valve for controlling said port, a movable abutment subject to opposing fluid pressures for operating said valve, and means governed by the triple valve for releasing air from one side of said abutment.

3. In afluid pressure brake, the combination with a triple valve having an exhaust port, of a valve for controlling said port, a movable abutment exposed on one side to train pipe pressure for operating said valve, and means governed by the triple valve for controlling communication from the auxiliary reservoir to the other side of said abutment.

4. In a fluid pressure brake, the combination with a triple valve having an exhaust port, of a retarded release valve device for controlling said port and comprising a valve and movable abutment subject on one side to train pipe pressure, and means operated by variations in train pipe pressure for controlling communication from the auxiliary reservoir to the opposite side of said movable abutment.

5. In a fluid pressure brake, the combination With a triple valve having an exhaust port, of a release valve for controlling said port, a piston exposed on one side to train pipe pressure for moving said valve to its closed or restricted position, means operated by the movement of the triple valve in applying the brakes to vent air from the opposite side of said piston,-and in releasing brakes to open communication from the auxiliary reservoir to said release position.

7. In a fluid pressure brake, the combination With a triple valve having an exhaust port, of a release valve for controlling said port, a piston normally subject to the opposing pressures of the train pipe and auxiliary reservoir for operating said valve, and means operating upon a reduction in train pipe pressure for venting air from the auxiliary reservoir side of said release valve piston.

8. In a fluid pressure brake, the combination with a triple valve having an exhaust port, of a release valve for controlling said port, a plsto-n sub ect on one side to. tram pipe pressure for operatlng said release valve, said triple valve having ports for opening communication from the auxiliary reservoir to the chamber on the opposite side of the release valve piston in release position, and for venting said chamber at an intermediate position.

9. In a fluid pressure brake, the combination with a triple valve having an exhaust port, of a release valve for controlling said port, a piston normally subject to the opposing pressures of the train pipe and the auxiliary reservoir for operating said release valve, said triple valve having ports for venting air from one side of the release valve piston in an intermediate position, and a spring normally tending to return the retarded release valve to its full release position.

In testimony whereof I have hereunto set my hand.

JOHN S. OUSTER.

Witnesses:

R. F. EMERY, J. B. MACDONALD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G. 

